Storage Overview
This topic describes the basic information related to LDC Hybrid Cloud (LHC) storage to help you understand the basic knowledge about and basic relationships between the corresponding modules when you use the storage feature.
In deployment environments that are based on the Apsara Stack infrastructure, the storage feature is dependent on the storage classes supported by Alibaba Cloud Container Service for Kubernetes (ACK).
Basic concepts
Storage class
Storage classes are a Kubernetes native concept and are usually defined by the system administrator. The storage classes specify the storage types supported. Different types vary in the storage service level agreement (SLA) and backup policies.
PV
PVs are a Kubernetes native concept. A PV represents a volume of a specific storage class in Kubernetes. A PV object defines the specific storage class and volume parameters. In other words, all OSS-related information is stored in PVs. In Kubernetes, the storage information in the PVs is referenced when storage mounting is performed.
PVC
PersistentVolumeClaims (PVCs) are a Kubernetes native concept. One PVC is bound with one PV. A PVC is an abstract PV type in Kubernetes and represents the data volume expression of a specific storage class.
Basic relationships
The following figure shows the relationships between a storage class, a PV, and a PVC.
PVC: describes the attributes of a PV that a pod needs to use, for example, the size and read/write permissions of the PV.
PV: describes the specific attributes of a volume, for example, the volume type and mount directory.
Storage class: serves as a PV template. Only PVs and PVCs belonging to the same storage class can be bound together. For more information, see Bind a PVC and a PV
References
For more information about Kubernetes storage, see Storage.
For specific storage-related operations, see the following topics: